UK economist Gerard Lyons said focusing on extreme wealth “does not always give the full picture” and attention should be paid to “making sure the economic cake is getting bigger”.

However, he said Oxfam was right to single out companies that it believed fuelled inequality with business models that were “increasingly focused on delivering ever-higher returns to wealthy owners and top executives”.

Oxfam’s Wright said economic inequality was fuelling a polarisation in politics, citing Donald Trump’s election as US president and the Brexit vote as examples.

“People are angry and calling out for alternatives. They’re feeling left behind because however hard they work they can’t share in their country’s growth,” she said.

The charity is calling for “a more human economy” and is urging governments to crack down on executive pay and tax evasion and impose higher taxes on the wealthy.

It also wants business leaders to pay a “fair share of tax” and has urged companies to pay staff the “living wage”, which is higher than the government’s National Living Wage.

Oxfam has produced similar reports for the past four years. In 2016 it calculated that the richest 62 people in the world had as much wealth as the poorest half of the global population.

The number had fallen to just eight this year because more accurate data was now available, Oxfam said.

It was still the case that the world’s richest 1% had as much wealth as the rest of the world combined, Oxfam said.

Some of the eight richest billionaires have given away tens of billions of dollars. In 2000 Bill Gates and his wife Melinda set up a private foundation that has an endowment of more than $44bn.

In 2015 Mark Zuckerberg and his wife Priscilla Chan pledged to give away 99% of their net worth in their lifetimes, which equated to about $45bn based on the value of Facebook shares at the time.

It takes cash and assets worth $71,600 to get into the top 10%, and $744,396 to be in the top 1%.

Oxfam’s report is based on data from Forbes and the annual Credit Suisse Global Wealth datebook, which gives the distribution of global wealth going back to 2000.

The survey uses the value of an individual’s assets, mainly property and land, minus debts, to determine what he or she “owns”. The data excludes wages or income.

The methodology has been criticised as it means that a student with high debts, but with high future earning potential, for example, would be considered poor under the criteria used, according to BBC.